Art of cracking hydrocarbons



Aug. 23, 1932. E. W. lsoM ART 0F'A CRAGKING `HYDROCRBONS Filed April 1e. 1929 lNvENToR Edu/ard l/V l'som ATTORNEYS E QM,

Patented Aug. 23, 1932 uNrrED s'rnras PATENT ogrrficli` EDWARD W. rso1vr,or scnnsnnta, NEW YORK, AssIeNon 'ro srNoLAra PANY, or NEW Yoax, N, Y.,

A CORPORATION OF MAINE lART or cRAoxING HYDROoAnBONs ,A

Application med April 16, 1929. serial No. 355,593.

This invention relates to improvements in the manufacture of lower boiling hydrocarbon Oils, such as gasoline, from higher boiling hydrocarbon oils, such as gas oil, by pressure distillation cracking operations.

In carrying out the present invention, the raw oil, together with reflux condensate, is heated to a cracking temperature and the vapors of the cracked oil are subjected to a reluxing operation under` superatmospheric pressure. Reflux condensate is discharged from the refluxing operation and the pressure on the discharged reflux condensate is re# duced as it is discharged. Cool raw oil is introduced into the discharged reflux condensate as the pressure thereon is reduced and before any vapors formed by the pressure reduction are separated therefrom. The discharged reflux condensate is thus cooled to a temperature such that higher boiling components suitable to be supplied to the heating operation remain liquid and the raw oil is preheated by absorbing heat which might otherwise be absorbed in the vaporization of such higher boiling components on pressure reduction. Vapors of lower boiling coniponents may be separated from the liquid mixture following the cooling operation. The resulting liquid mixture, including raw oil components and reflux condensate com ponents, is supplied to the heating operation.

The sepa-ration of vapors of lower boiling components from the liquid mixture following the cooling operation may be carried out, for example, as described in application Serial No. 222,911, tiled September 29, 192'?, by Eugene C. Herthel.

The invention will be further described in connection with the acompanying drawing which illustrates diagrammatically and conventially, in elevation and partly in section and with parts broken away, one form ot apparatus adapted for carrying out the invention.

Referring to the drawing, a raw oil-reflux condensate mixture is forced from the supply tank 1 through theheater 2 by means of the pump 3. The oil is-heated to a cracking temperature in the heater 2 and the resulting hot oil products are discharged into the drum Ll.

In the drum l, vapors and' residualoil arev separated; the vapors escapefthrough the rellux tower 5 and theresidual oil is discharged through connection 6. Reflux condensate flows from thereilux tower' 5 to the supply tank 1 through connections 7 and 8. .-Vapors escape from the reflux tower 5 to the .condenser 9 through connection 10.

The drum t vand the reluxtower 5 are maintained under superatmospheric pressure by means of the valves 11, 12Aand713 in the connections 6, 7 and' 10 respectively- Valve 13 is regulated to maintain and control the pressure in the drum and the rellux tower 5. Valve 12Vis regulated Y of reflux condensate from the reflux tower 5. Valve 11 is regulated to control the. discharge ofresidual oil Jfrom the drum t.

. The heater 2 comprises a group of. series connected heating tubes arranged in the heating flue of heating furnace 1li.

The condenser 9 isv arranged to discharge into the receiverl 15. The condensed dis'- tillate product is discharged from the receiver 15 throughconnection 16, uncondensed vapors and gases being discharged through connection 17. The operation of the refluxv tower v5 may be controlled by circulation of a cooling medium throughnthe cooling coil 18, .by the direct introduction of a part of the distillate product through connections 19 and '20 or of some similar fraction through connections 21 and 2O by means of pump 22, or by the direct introduction ofa part of the raw oil f supplied to the operation through connections 23 and 24C by means of pump 25, or by anyof these means conjointl i 1 In carrying out this invention in thev apparatus illustrated, coolraw oilis introduced REFINING colvr- 'i to control the'discharge into the discharged reflux condensate flowing through connection 8 after passing through valve 12 through connection 26. The resulting mixture of reflux condensate and raw oil is required to flow through connection 8 before any vapors formed by the pressure reduction on the discharged reflux condensate can separate from the oil mixture. This cool raw oil, introduced into the discharged reflux condensate through connection 28, may be supplied through connection 27 by means of pump 25 or through connection 28 by means of pump 29.` Higher boiling raw oil' may be supplied by means of pump 29 and relative ly lowerboiling vraw oil may be supplied by means of pump 25, for example,"or but a single raw stock may eration by means Vof be supplied to the oppump 25. Any excess subjecting vapors of the cracked oil to a re-k fluxing operation under superatmospheric pressure, discharging refluxv condensate from therefluxing operation into a vapor separatJ ing zone and reducing the pressure on the discharged -refiux condensate, introducing cool oil into the discharged reflux condensate as the pressure is reduced thereon and before separation of any vapors formed by the pressure reduction in an amount sufficient to reduce vthe temperature of the mixture to less than about l5@O F., sep-aratelydischargling vapors from said vapor separatingzcne and supplyingthe remaining liquid oil mix: ture to the heating operation; 1

In testimony whereof I aix my signature.

EDWARD W. ISOM.

oil accumulating in thel supply'tank 1 may Y be discharged through connection 30. Any vapors or gases separating in the supply tank 1 may be dischargedthrough connection 31.

Drum 4,' thereflux tower 5 and the supply tank 1 are with advantage lagged or thermally insulated.

Lower boiling components, suitable as com- Y ponents of the distillateproduct for example, maybe separated as vapors from the oil mixture in the supply tankr 1 and discharged through connection 31' to a suitable condenser or 'other recovery apparatus. Such lower boiling components may be components of reflux condensate formed in the reflux tower 5 or components of raw oil supp-lied throughv connection26 kor throughfconnection 24.

The following example of an operation embodying the invention yas carried out in the apparatus illustrated will furthery illustrate the invention: Gas oil at a temperature ofy (iO-80 F. is supplied through connections 28 and 26 by means of pump 29 at a rate Vsufficient to maintain the temperature of the oil mixture in the supply tank 1 below about 450 F.'or better 350 F. The oil mixture from the Vsupply tank 1 is heated to a temperature approximating E550-950o F. as discharged from the heater 2. The cooling inedium isccirculated through thev cooling coil I 18 ata rate regulateds'o that vapors` escape from thereflux tower at a temperature in the neighborhood of 37 5-150o F. Thedrum A 4 and the reiiux tower 5 aremaintained under a pressure inthe neighborhood of 100 i pounds per square inch, controlled by the valve 13. A distillate including the gasoline product is collected in the receiver .15. It a willbe understood that the foregoing ex- Y ample is intended to illustrate theinvention and that the `invention is not limited to 'these specific conditions ,of operation. v

IV claim:

In cracking higher boiling hydrocarbonY 'y ,e oils to produce lower boilinghydrocarbon oils Y therefrom, the improvement which comprises heating the oilto a cracking temperature and 

